From patchwork Mon Sep 26 23:20:28 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Begunkov X-Patchwork-Id: 12989588 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C1B55C07E9D for ; Mon, 26 Sep 2022 23:23:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231281AbiIZXXz (ORCPT ); Mon, 26 Sep 2022 19:23:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37620 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230464AbiIZXXa (ORCPT ); Mon, 26 Sep 2022 19:23:30 -0400 Received: from mail-wm1-x32f.google.com (mail-wm1-x32f.google.com [IPv6:2a00:1450:4864:20::32f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B40974CFD for ; Mon, 26 Sep 2022 16:21:41 -0700 (PDT) Received: by mail-wm1-x32f.google.com with SMTP id l8so5498885wmi.2 for ; Mon, 26 Sep 2022 16:21:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date; bh=2lSUpe592kbPQPhQMkeGWB6/Vun9yDD9GrzMvVsq/YE=; b=JFbAjsOf6gkvU2GaAnBFENd3hLGFO8h2NWD77dSXj1bf6R8YMQhAOAKRgS1GguZODi mMWUwIcBxp8oMowWSmqmooyQE8Ui8DGey2yyqCMn0PrnQSphOLdHYV9sqaCkWi3J8Z71 ujS58zLsqNRstIljwi/BiKQSRGan2yCrK8ToOD/6tmLmiax2KRqKrHyL2VbtC+GWYlTI Wd+juE6H8Bzv9SvrgJc8ORLrGUT/rGNhFJHze6jMTRjxuJWd9JOru/P2NJO+5wzIejui SJsgic1C/OHKFpigsmAoQkC3IfHmwzIbTReZv5jq4WjZ65QuyxlSlgwVlycLigCNgSvq CPUQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date; bh=2lSUpe592kbPQPhQMkeGWB6/Vun9yDD9GrzMvVsq/YE=; b=22JgSs5zwI8My6VvGi2trea14e0BJnp6fRWbj67Jz3dnRu0kdM7wztB0B3TEKSQ+fL PPLfTkVMNKSuSK+RsNwnr/+3XdPy5TvXGQnNrHpgA8G+gwfqIgF8q1DOpgCCPA/9JnXO joOu3loQxurFg/KP2cJDFtgy6PIujPf4Domt2i12fe69NP2qHeHueIdYGNiKE8qmqtUd G2aZECA4khvid8AsDN44UDN0hO/xH6nF6HlbbbVMSuebcPqQVBsDuHDTrLJvIUmryIRt ISpc2Mw9S/N8lfvsXDQdd59+l73sQvVkm0Vc0MNZy2pawbZnxOxQT26DgVH72XpdTU/U TEXg== X-Gm-Message-State: ACrzQf1NWHMbRA1dgaUuzdp10stA6CEKwJf1KpMbZZn/b2Ugb3oRZR7Z gvbRbjq/WJf+5VmTIqTQnRfiXAZLspM= X-Google-Smtp-Source: AMsMyM5BoDLsOTFAfDL386+fPjg+8rwxIFtbUFGximKW1UCOcJU5xowKivua312gQyRza1tybn0Ukw== X-Received: by 2002:a7b:c450:0:b0:3b4:fb1a:325d with SMTP id l16-20020a7bc450000000b003b4fb1a325dmr654012wmi.138.1664234499131; Mon, 26 Sep 2022 16:21:39 -0700 (PDT) Received: from 127.0.0.1localhost (94.196.228.157.threembb.co.uk. [94.196.228.157]) by smtp.gmail.com with ESMTPSA id p16-20020adfe610000000b00225239d9265sm90616wrm.74.2022.09.26.16.21.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 26 Sep 2022 16:21:38 -0700 (PDT) From: Pavel Begunkov To: io-uring@vger.kernel.org Cc: Jens Axboe , asml.silence@gmail.com, Beld Zhang Subject: [PATCH for-next 1/2] io_uring/rw: fix unexpected link breakage Date: Tue, 27 Sep 2022 00:20:28 +0100 Message-Id: X-Mailer: git-send-email 2.37.2 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org req->cqe.res is set in io_read() to the amount of bytes left to be done, which is used to figure out whether to fail a read or not. However, io_read() may do another without returning, and we stash the previous value into ->bytes_done but forget to update cqe.res. Then we ask a read to do strictly less than cqe.res but expect the return to be exactly cqe.res. Fix the bug by updating cqe.res for retries. Cc: stable@vger.kernel.org Reported-by: Beld Zhang Signed-off-by: Pavel Begunkov --- io_uring/rw.c | 1 + 1 file changed, 1 insertion(+) diff --git a/io_uring/rw.c b/io_uring/rw.c index 76ebcfebc9a6..c562203d7a67 100644 --- a/io_uring/rw.c +++ b/io_uring/rw.c @@ -823,6 +823,7 @@ int io_read(struct io_kiocb *req, unsigned int issue_flags) return -EAGAIN; } + req->cqe.res = iov_iter_count(&s->iter); /* * Now retry read with the IOCB_WAITQ parts set in the iocb. If * we get -EIOCBQUEUED, then we'll get a notification when the